Bad Injector=low rail Pressure=no start?

[dan shss]

I have low rail pressure and the truck wont start. I changed the FCA and that didnt fix my no start. If i unplug the fca and then crank it over it will start. Our if I pinch the return line going to the cp3 it will start...



When I get it started and spray water on the exhaust manifold on all the cylinders #6 is cold and not firring all the other cylinders are making heat. . So can the injector bypass that much fuel to create a low rail pressure no start without leaking fuel in the cylinder ?



Im not getting any fuel in the oil our white smoke on start up,And this is the truck in my sig

 

[JStieger]

So can the injector bypass that much fuel to create a low rail pressure no start without leaking fuel in the cylinder ?



Im not getting any fuel in the oil our white smoke on start up,And this is the truck in my sig

If your connector tubes to the injectors are not torqued properly then the fuel rail pressure will not build up and fuel will leak down through the fuel return channels and out the return line at the back of the head - all without getting into your oil.



When you disconnect the FCA the ECM defaults to commanding the highest rail pressure it can so the CP3 runs full tilt trying to put out about 23,000 psi or so. That's why your truck started - it was easily getting more than the minimum required rail pressure to start.

 

[CStraface]

Im not getting any fuel in the oil our white smoke on start up,And this is the truck in my sig

Does white smoke at start up mean you have a bad injector?

 

[Summit]

How do you know you have low rail pressure? Have you checked the pressure relief valve?



is it knocking at all? i asume it's the white 03 and not the 06.

 

[dan shss]

If your connector tubes to the injectors are not torqued properly then the fuel rail pressure will not build up and fuel will leak down through the fuel return channels and out the return line at the back of the head - all without getting into your oil.



When you disconnect the FCA the ECM defaults to commanding the highest rail pressure it can so the CP3 runs full tilt trying to put out about 23,000 psi or so. That's why your truck started - it was easily getting more than the minimum required rail pressure to start.

I will check and tighten my crossover tubes and go from there,do you thing this would be enough to not let the injector fire?

 

[dan shss]

How do you know you have low rail pressure? Have you checked the pressure relief valve?



is it knocking at all? i asume it's the white 03 and not the 06.

I dont have a rail pressure gauge but when I get rail pressure It starts, No I have not checked the PRV but that would not explain my one bad injector, Yes it runs rough when I get it running,and yes its the 03.

 

[JStieger]

I will check and tighten my crossover tubes and go from there,do you thing this would be enough to not let the injector fire?

Yes... happened to me once as well as a friend of mine.



You had mentioned earlier that you pinched the return line and it started. This tells me you are back pressuring up the return from #6 just enough to get it to start. The crappy part is having to access #6 connector tube nut with all the stuff in the way. Maybe a 24 mm crows foot attached to a small torque wrench with flex or u-joint connector should get you there.

 

[dan shss]

Yes... happened to me once as well as a friend of mine.



You had mentioned earlier that you pinched the return line and it started. This tells me you are back pressuring up the return from #6 just enough to get it to start. The crappy part is having to access #6 connector tube nut with all the stuff in the way. Maybe a 24 mm crows foot attached to a small torque wrench with flex or u-joint connector should get you there.

Thank you all for the help,I will report back tommorow with the results.

 

[dan shss]

I tightened the fuel cross over tube and this still didnt fix my no start... It must just be the ball and seat in the injector not sealing. .



Anyone have any good used Injectors our Injector for sale?